Objective: To determine whether suspicion for tumor on prostate MRI incorporating T2-weighted imaging (T2-WI) and diffusion-weighted imaging (DWI) predicts more adverse pathology on radical prostatectomy (RP). Methods: From 2007 to 2009, 154 patients underwent 1.5 Tesla pelvic-phased-array magnetic resonance imaging (MRI) of the prostate that included T2-WI and DWI before RP. MRI examinations were retrospectively reviewed and grouped by degree of suspicion for tumor: no suspicion for tumor (NST, n = 15), equivocal suspicion for tumor (EST, n = 60), or strong suspicion for tumor (SST, n = 79). The NST/EST groups were combined and compared to the SST group. Preoperative variables were used to assemble a multivariate model. Outcomes reflective of adverse pathology included primary Gleason grade ≥4, pathologic stage ≥T3 (≥pT3), and tumor upgrading. Subgroup analysis was performed for patients meeting eligibility criteria for active surveillance (n = 55). For this analysis, the NST group was compared to the EST/SST groups. Results: SST status was associated with adverse preoperative risk factors for aggressive disease. Univariate analysis demonstrated significant association between SST and primary Gleason ≥4 pathology and stage ≥pT3 (P <.05). On multivariate analysis, SST was independently predictive of primary Gleason ≥4 pathology (odds ratio [OR] 6.14, 95% confidence interval [CI] 1.97-19.2) and Gleason upgrading (OR 2.47, 95% CI 1.01-6.02). Among patients eligible for active surveillance, those in the NST group had decreased likelihood of Gleason ≥7 disease or stage ≥pT3 compared to the EST/SST groups (7.7% vs 47.6%, P =.01). Conclusion: Increased tumor suspicion on T2-WI/DWI MRI is indicative of adverse pathology on RP. These findings suggest a role for MRI in pretreatment risk assessment.
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